That would be the case if it were not for the fact that it is really good at surviving in the human body.... until the person is dead or until they have developed antibodies to fight it. Some people do survive Ebola (aka the plague or the black plague). But not many. Ebola spreads, and fast at that, in areas where there are high population densities, areas where people are in close contact (areas like NYC). Because of the symptoms, it is possible that someone may be infected, spreading the disease, but think they have the flu or some other common ailment. That is the reason why the hospital in the original article didn't take chances and put the person in involuntary quarantine (the article didn't say it but I can guarantee that is the case (and the patient may not know it because if you had Ebola you would have to be insane to decline care)). The only effective way to fight Ebola is quarantine. You section off an area, don't let anyone in or out, and wait out the sickness until it runs it course. After that you safely and securely destroy everything.